Nope the 5 bolt discs are completely incompatible with IS standard 6 bolts. No conversion.
6 bolt discs are available in c2 sizes direct from hope, orderable at your LBS or from a kind soul on here. easiest way to tell a c2 disk is that they come in 145,165,185 and 205mm sizes. Standsrd XC fit was generally 145 rear and 165 front. Also some places do the same but in 183mm etc that will also usually fit.
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Best way to tell which caliper you have is to look for the number carved on it. 3 & 5 are the common IS mount ones.